Tube Buffer vs Tube Pre-amplifiers?

[Guddu]

*** Please don't convert this thread into an attack on tube products ***
*** We know tube adds distortion, we have seen it in measurements ***

Those who are interested in Tube Products and have exposure to Tube Buffer and Tube Pre-amplifiers, please explain the differences and observations.

To start with - I have tried a few tube products, mostly sub-100$ tube pre-amplifiers you see on Amazon.
- They look nice when glowing, most of them have volume control with tone controls which essentially work
- I have not found them causing something to the sound that I could hear, but they did provide strong pre-amped signal

Now, someone tells me that I should try tube buffer which basically does not pre-amp the signal and rather do something else.
I have not found any speacific tube buffer being measured anywhere, and so asking here.

What do you know?
How a tube buffer is different?
Does it add or do anything better?
Do you have any recommendations?

 

[firedog]

With tube products you don’t know what you are going to get: some add a lot of tube coloring/distortion and some don’t.
I’ve had a tube buffer from Yaqin that added a lot of color/distortion. Too much for me.
A buffer shouldn’t boost the signal if it is doing its job. It is supposed only to add the tube color. You should check other forums and find out which ones people are happy with and why.
I have a tube pre-amp that I can option in or out of my chain (it’s usually out) that adds a bit of warm sound and “solidity” to the sound, if I’m in the mood for adding in that distortion. It adds only a bit, so I don’t mind it.

 

[DVDdoug]

A real buffer is a circuit with no gain or attenuation and it boosts the current capability (lowers the impedance). i.e. A guitar pickup likes to see a load of about 1 megohm. If you run it through a buffer you'd get the same voltage but you could plug it into a line input with an impedance between 10K - 100K.

A "tube buffer" for a guitar could do that, but normal line-level signals are already (relatively) low impedance and it might even do the opposite. (Tubes "naturally" have higher output impedance than solid state electronics, and they also have very-high input-impedance). A buffer is just an active circuit with no gain (a gain of 1.0) and a tube buffer possibly adds distortion.

A preamp is obviously more versatile. A regular hi-fi preamp has and a volume control that can adjust between gain and infinite attenuation, multiple inputs, usually tone controls and other controls.

Phono preamps & microphone preamps have high gain.

*** We know tube adds distortion, we have seen it in measurements ***

Not necessarily. It's not hard to build an audibly transparent tube preamp or buffer.

Tube power amps are a different story because they have an output transformer. It's difficult and expensive to make a good tube power amp.

Ther is no one "tube sound" (although there is a tendency for tubes to soft-clip when over-driven). If a tube amp has audible distortion, it's going to sound different from another tube amp. If you want tube distortion you have to listen to the particular amp and decide if you like it.

Guitar players often prefer tube amps for the way they sound when over-driven. Guitar amplifiers are not high-fidelity. They are "part of the instrument" and most guitar players have their favorite guitar and their favorite amp.

Does it add or do anything better?

Most people don't like audible distortion. The concept of high-fidelity is to faithfully-accurately reproduce the recording.

Do you have any recommendations?

Avoid 1950s technology. It can sound just as good as solid state electronics but it's more expensive, tubes are energy-inefficient, and they age and eventually burn-out.

 

[Gorgonzola]

As I recall going back a good many years ago tube buffers tout as ostensibly lowering the output impedance of the upstream devise making the combination a better match for downstream amps, especially those with low input impedance. Some tube preamps already had integral "cathode follower" tube circuits that had the same purpose. ... Tech-savvy folks will correct me it I'm wrong about that.

However most buffer users twigged to the fact that those tube buffers slightly modified the sound towards more 'warmth' and 'smoothing' of the sound.

I currently use tube preamp, (Sonic Frontiers Line 1), that uses to separate tubes to (i) buffer inputs, (ii) provide gain, and (iii) act as cathode followers, a.k.a. output buffers.

 

[Guddu]

I have a tube pre-amp

mind telling which product?

 

[Guddu]

Cool.... I think I have read some of these comments in some other forum post while searching through internet, might be your original comments from there.

I don't really care transparent or distortion.
I have a transparent system already, quest is to see what a tube sound is as gazillion people say on internet.
If distortion is changing the sound then so be it.

I understand what you are saying here, but there is nothing wrong in tuning a song the way you like.

 

[Guddu]

As I recall going back a good many years ago tube buffers tout as ostensibly lowering the output impedance the upstream devise making the combination a better match for downstream amps, especially those with low input impedance. Some tube amps already had integral "cathode follower" tube circuits that had the same purpose. ... Tech-savvy folks will correct me it I'm wrong about that.

However most buffer users twigged to the fact that those tube buffers slightly modified the sound towards more 'warmth' and 'smoothing' of the sound.

I currently use tube preamp, (Sonic Frontiers Line 1), that uses to separate tubes to (i) buffer inputs, (ii) provide gain, and (iii) act as cathode followers, a.k.a. output buffers.

View attachment 381426

Which product is this?

 

[DVDdoug]

As I recall going back a good many years ago tube buffers tout as ostensibly lowering the output impedance the upstream devise making the combination a better match for downstream amps

An op-amp can do that. Usually better and certainly cheaper. A buffer is about the simplest thing you can make with an op-amp.

I currently use tube amp that uses to separate tubes to (i) buffer inputs, (ii) provide gain, and (iii) act as cathode followers, a.k.a. output buffers.

Yes! A buffer is usually a circuit inside an amplifier (or other audio device). It's usually not a stand-alone device.

 

[DSJR]

I used to sell the MF X-10D valve-tube buffer. It was marketed as an impedance matcher for lower cost CD players, something I now realise isn't really a problem, but its added tonal 'warmth' helped with slightly acidic or rough mid price players such as the Marantz CD63 KI Signature, which sold by the container load back in its day. Decades later, I bought an X-10D to play with and indeed, it added a slightly dirty 'bloom' to the 'sound' of signals played through it. A vendor, 'Rock Grotto,' did a full update kit (since revised) which I bought and fitted, including fresh Russian mil-spec valves which he didn't charge a fortune for. Having done the update, the 'bloom' all but disappeared, the thing having next to no 'sound' to it any more at all on insertion and basically rendering its use redundant frankly. I still have it stored away, but not sure if I'd ever need to use it unless forced to use a passive preamp which my current power amps don't like at all!

Before -

After -

 

[dasdoing]

why not use software? it can give you as much saturation as you want, and of the type you wish to, and you can adopt it when changing genres

 

[DVDdoug]

but there is nothing wrong in tuning a song the way you like.

True, but... It would be better if you had a distortion control*. You may not want the same distortion on every recording. And typically, you're getting clipping (overload distortion) so it depends on the loudness, but the peaks not the perceived loudness.



* For audio production there are digital plug-ins where you can dial-in various kinds and amounts of distortion/saturation. There are effects that simulate tube saturation or tape saturation and some model the sound of a particular guitar amplifier. A compressor/limiter can do similar things. These generally integrate with a DAW application so they aren't easy to use "at home" or for everyday listening.

P.S.
You CAN buy a hardware compressor/limiter.

 

[dlovesmusic]

mind telling which product?

A Schiit Freya + can do that. It has an optional tube stage with 4 6SN7 tubes. It also has a solid state active mode and also has a passive preamp mode that is simply a transparent pass through.

 

[MAB]

I used to sell the MF X-10D valve-tube buffer. It was marketed as an impedance matcher for lower cost CD players, something I now realise isn't really a problem, but its added tonal 'warmth' helped with slightly acidic or rough mid price players such as the Marantz CD63 KI Signature, which sold by the container load back in its day. Decades later, I bought an X-10D to play with and indeed, it added a slightly dirty 'bloom' to the 'sound' of signals played through it. A vendor, 'Rock Grotto,' did a full update kit (since revised) which I bought and fitted, including fresh Russian mil-spec valves which he didn't charge a fortune for. Having done the update, the 'bloom' all but disappeared, the thing having next to no 'sound' to it any more at all on insertion and basically rendering its use redundant frankly. I still have it stored away, but not sure if I'd ever need to use it unless forced to use a passive preamp which my current power amps don't like at all!

Before -

View attachment 381428

After -

View attachment 381429

It was tested:

Musical Fidelity X-10D line-level preamplifier Measurements

Sidebar 3: Measurements Although it could be conjectured that the presence of tubes in the X-10D might add a certain thermionic something to its sound, there was nothing in the measurements that would confirm that hypothesis. In fact, the Musical Fidelity appears to use a well-engineered...

www.stereophile.com

It's a nice piece of clean tube gear, I personally couldn't hear the impact, it's transparent, unless it fixed some odd impedance mismatch.
Which begs the question; why tubes? I asked the question repeatedly while owning Sonic Frontiers preamp and amp.

 

[Verig]

To start with - I have tried a few tube products, mostly sub-100$ tube pre-amplifiers you see on

I wouldn't call most of them tube products. There's a tube and a led. If you're lucky the tube is even in the signal path...
Buy a used Musical Fidelity X-10D mentioned above if you want something nice.

 

[Verig]

For real tube sound (in good and bad) buy yourself a nice 300B SET amp. I guarantee you don't need to look for differences with a magnifier.

Pre and buffers are supposed to be clean and they're easy to make clean (enough). Power amps on the other hand will do wild things if you want but even the it's the low power SETs you want. Some 100W@8R monster won't sound very "tube" at all.

 

[Robin L]

Sorry, I can't recall the company that made them. But back in the 1990s I used a "starved tube" microphone preamp along into a Mackie mixer for recording. The starved tube preamp was a single space rack mount piece. It had the subjective effect of limiting peaks in a smooth and unobtrusive fashion. I used it all the time for my main pair of microphones, worked well.

 

[MAB]

*** Please don't convert this thread into an attack on tube products ***
*** We know tube adds distortion, we have seen it in measurements ***

Those who are interested in Tube Products and have exposure to Tube Buffer and Tube Pre-amplifiers, please explain the differences and observations.

To start with - I have tried a few tube products, mostly sub-100$ tube pre-amplifiers you see on Amazon.
- They look nice when glowing, most of them have volume control with tone controls which essentially work
- I have not found them causing something to the sound that I could hear, but they did provide strong pre-amped signal

Now, someone tells me that I should try tube buffer which basically does not pre-amp the signal and rather do something else.
I have not found any speacific tube buffer being measured anywhere, and so asking here.

If you have spare money, and can measure and evaluate what it actually is doing, it might be worth your effort in the sense that playing around with gear is kinda fun. I wouldn't buy unless you plan on actually determining if it makes a difference. Asking friends for sonic impressions is surefire way to keep throwing money at gear though. I've had lots of tube gear over the years, the only stuff I ended up keeping was transparent (and reliable) like Sonic Frontiers and Audio Research. Both are virtually indistinguishable from solid state, and don't burn through tubes, don't spray harmonic distortion, and had low enough amplifier output impedance that they didn't affect the frequency response (actually the most audible thing in most tube amps, NOT the supposed even-order distortion that people claim they know all about, potentially may need to revise your asterisked opinion on what tubes do and don't do). Same applies for the X-10D mentioned, it is utterly transparent.

What do you know?
How a tube buffer is different?

Gain is typically = 1

Does it add or do anything better?

If done correctly, adds nothing except addresses impedance mismatches (that are unlikely to exist in most systems with reasonably designed gear).

Do you have any recommendations?

Measure, don't listen if you actually want to determine differences!

 

[DSJR]

It was tested:

Musical Fidelity X-10D line-level preamplifier Measurements

Sidebar 3: Measurements Although it could be conjectured that the presence of tubes in the X-10D might add a certain thermionic something to its sound, there was nothing in the measurements that would confirm that hypothesis. In fact, the Musical Fidelity appears to use a well-engineered...

www.stereophile.com

It's a nice piece of clean tube gear, I personally couldn't hear the impact, it's transparent, unless it fixed some odd impedance mismatch.
Which begs the question; why tubes? I asked the question repeatedly while owning Sonic Frontiers preamp and amp.

OWWWWW - $499 back then?

We sold it for £120 which made it a cheap add-on for those interested. It came with a chunky 12VAC transformer and there was an option of a higher current four output supply in the same cylindrical case to power the valve pre, phono stage and (back then, nice sounding) dac they did. I believe Tim de P had his hand in the design of these units.

I maintain the original *did* put a sonic flavour on everything passed through it, but have to agree that distortion was low, bandwidth wide and overload not until way over 2V (several volts it seems), kind-of suggests it should be transparent.

My 'updated Rock Grotto' sample is now as transparent as it needs to be and doesn't at all effect the signal audibly.

Musical Fidelity X-10D upgrade Kit

 

[Zek]

You CAN buy a hardware compressor/limiter.

These are devices for musicians (electric guitar, electric bass, organ, etc.) not intended for use in a home hi-fi chain.

 

[MAB]

OWWWWW - $499 back then?

We sold it for £120 which made it a cheap add-on for those interested. It came with a chunky 12VAC transformer and there was an option of a higher current four output supply in the same cylindrical case to power the valve pre, phono stage and (back then, nice sounding) dac they did. I believe Tim de P had his hand in the design of these units.

I maintain the original *did* put a sonic flavour on everything passed through it, but have to agree that distortion was low, bandwidth wide and overload not until way over 2V (several volts it seems), kind-of suggests it should be transparent.

It was a surprisingly good piece of gear.
Sadly, no associated pieces we sold had odd enough impedance mismatches to take advantage of the main feature; a buffer.